Microfluidics, the manipulation of fluids in channels with micron dimensions, has emerged as an exciting new field that impacts the broad area of nano/microtechnology. This is an important area to train the next generation of chemical engineers. This paper describes an experiment where students are given a problem to design a microfluidic mixer that can be used to mix two fluids. The students design, fabricate, and test their device using computer aided design, soft lithography, and image analysis software. This lab demonstrates fundamental fluid mechanics and mass transport principles.